EC - Methyltransferase cap1

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IntEnz Enzyme Nomenclature


Accepted name:
methyltransferase cap1
Other names:
messenger RNA (nucleoside-2'-)-methyltransferase
messenger ribonucleate nucleoside 2'-methyltransferase
mRNA (nucleoside-2'-O)-methyltransferase [ambiguous]
S-adenosyl-L-methionine:mRNA (nucleoside-2'-O)-methyltransferase
Systematic name:
S-adenosyl-L-methionine:5'-(N7-methyl 5'-triphosphoguanosine)-(ribonucleotide)-[mRNA] 2-O-methyltransferase



This enzyme catalyses the methylation of the ribose on the first transcribed nucleotide of mRNA or snRNA molecules. This methylation event is known as cap1, and occurs in all mRNAs and snRNAs of higher eukaryotes, including insects, vertebrates and their viruses. The human enzyme can also methylate mRNA molecules that lack methylation on the capping 5'-triphosphoguanosine [6].

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0004483
CAS Registry Number: 61970-02-3
UniProtKB/Swiss-Prot: (88) [show] [UniProt]


  1. Barbosa, E. and Moss, B.
    mRNA(nucleoside-2'-)-methyltransferase from vaccinia virus. Purification and physical properties.
    J. Biol. Chem. 253 : 7692-7697 (1978). [PMID: 701281]
  2. Barbosa, E. and Moss, B.
    mRNA(nucleoside-2'-)-methyltransferase from vaccinia virus. Characteristics and substrate specificity.
    J. Biol. Chem. 253 : 7698-7702 (1978). [PMID: 701282]
  3. Boone, R.F., Ensinger, M.J. and Moss, B.
    Synthesis of mRNA guanylyltransferase and mRNA methyltransferases in cells infected with vaccinia virus.
    J. Virol. 21 : 475-483 (1977). [PMID: 833934]
  4. Ensinger, M.J., Martin, S.A., Paoletti, E. and Moss, B.
    Modification of the 5'-terminus of mRNA by soluble guanylyl and methyl transferases from vaccinia virus.
    Proc. Natl. Acad. Sci. USA 72 : 2525-2529 (1975). [PMID: 1058472]
  5. Groner, Y., Gilbao, E. and Aviv, H.
    Methylation and capping of RNA polymerase II primary transcripts by HeLa nuclear homogenates.
    Biochemistry 17 : 977-982 (1978). [PMID: 629955]
  6. Werner, M., Purta, E., Kaminska, K. H., Cymerman, I. A., Campbell, D. A., Mittra, B., Zamudio, J. R., Sturm, N. R., Jaworski, J., Bujnicki, J. M.
    2'-O-ribose methylation of cap2 in human: function and evolution in a horizontally mobile family.
    Nucleic Acids Res. 39 : 4756-4768 (2011). [PMID: 21310715]

[EC created 1981 (EC created 1981, incorporated 1984), modified 2014]